Motor fuel blend and process of making the same



Patented Jan. 26, 1937 PATENT OFFICE MOTOR FUEL BLEND .AND PROCESS fMAKING THE SAME Frank Howard, Elizabeth, N. J., assignor to .StandardfOil. Development Company, a corporation 'oif Delaware Nd. Drawing,,.Application January 21, 1933, Y 1 Serial No. 652,931

zflclai ns. (01. 44-9) This invention relates to improvements in motor fuels (gasoline, naphthas and the like) containing pine oil or its efiective constituents, to-

gether with a substance adapted to prevent or.

decrease deposition of gum. The principal ob ject of the invention is to facilitate themanu-.

facture of blends of gasoline with organic compounds. It is known that pine oil, and its component terpenes, also terpineol, are mutual solvents for gasoline and organic compounds, for example, various alcohols which are themselves not very soluble in gasoline. It has been found, however, that such blends are objectionable as motor fuels because of their tendency to deposit gum. This tendency cannot be prevented to a satisfactory extent by the gum inhibitors now commercially available.

In a preferred form of the invention, pine oil is added to gasolinetogether with a small amount of an organic material serving as a gum flux or gum solvent. More specifically, the invention includes the use of pine oil or its components as a blending agent in the formation of gasolinealcohol motor fuels, a very small amount of a viscous hydrocarbon oil, of a type hereinafter defined, being used as the gum flux or solvent. The invention will be described with particular reference to this embodiment, but it is not limited thereto.

Blends of gasoline and alcohol, such as ethyl and isopropyl alcohols, and blends of gasoline with mixtures of methyl and higher alcohols, have been used and their- .advantages frompcertai'n I 1 automobile use in temperate climates.

standpoints are well recognized. The alcohols are normally available at low price only when The difficulty is to -se.

containing some water. cure a concentration of such alcohol in the gasoline which shall be sufi'icient and permanent. Since the alcohols are more soluble in water than in gasoline, any addition of water tends to cause a separation. Blending agents such as pine oil not only facilitates solution of the alcohol but increases its water tolerance, that is, itsability to stay in solution in gasoline notwithstanding the presence of limited amounts of water. Water tolerance may be measured by the amount oi. water (in percent by volume) necessary to produce the first appearance of a cloud with an alcohol blend at a fixed temperature.

Pine oil enables one to blend with gasoline, alcohols which are not; anhydrous, and also to protect blends of gasoline with anhydrous alcohol from separation by contamination with water. The amount of pine oil varies generally from 2-10 parts by volume of the gasoline-alcohol blend. This quantity may be varied, however, and depends in part upon the temperature to which the gasoline is likely to be subjected. As the temperature is lowered, water tolerance is decreased but this can be compensated for by adding larger quantities of pine oil.

' I have discovered that by the addition of minute quantities of viscous hydrocarbon oils, generally from 0.2-2.0 parts by volume of the blend,

the gum depositing tendency of gasoline-alcoholpine oil blends may be overcome. The following compositions are illustrative.

Parts by volume Ethyl alcohol 195%) 25 Motor gasoline 75 Pine Oil Viscous hydrocarbon oil 0.3

, Parts by volume Ethyl alcohol (95%) 5 Gasoline, aviation grade 95 vPine oil'- 10 Viscous hydrocarbon 0.5

' III i Parts by volume Isopropyl alcohol (97%) 35 'Motorgasoline 65 Pine oil Gulf coastal lubricating oil 1.0

Composition I is well adapted for ordinary Composition IIis designed particularly for aviation use where a small percentage of alcohol is desired chiefly for preventing the clogging of lines by freezing of moisture in the gasoline. The alcohol present lowers the freezing point of the water I sufliciently to prevent this difllculty. Composition 'III- is made up with a smaller percentage of pine oil, since the water tolerance of isopropyl alcohol isthe best of the commercially available alcohols.

' Instead of using ethyl alcohol or isopropyl alcohol I may substitute secondary butyl alcohol, or blends of methyl alcohol with hexyl and heptyl alcohols, etc., in approximately the same proportions or in any desired proportion.

The viscous hydrocarbon oil, generally of the mineral lubricating oil class, is preferably of the naphthenic typ such as Gulf coastal, West Texas, or Venezuelan oil. Hydroformed oils may be used with advantage. Highly purified heavy oils such as viscous .white oils or the like may be used but are usually less desirable. The effectiveness of any oil for the present purpose may be measured by its solvent power on the kauri butanol test scale. This test is described in circular 378, February 1931, of the American Paint and Varnish Manufacturers Association. In general oils that rate or higher on this scale are most desirable, but others may be used. The viscosity of the oil should usually be between 75-400 sec. Saybolt at 100 F., the A. P. I. gravity between 18 and 28, and the viscosity index less than 30. These properties, however, are subordinate to the gum solvent or fluxing capacity of the oil. Any desired mixture of oils may be used to secure the required properties.

Instead of using lubricating oils of the type described as the gum flux or solvent, I may use a variety of other substances, for example organic compounds, such as secondary amyl stearate, esters of acids obtained by oxidizing parafiin wax, hexamethyl phenyl acetylene, etc., in approximately the same proportion which materials have a kauri butanol value above 15.

Instead of alcohol as the material to be blended with gasoline this invention may be advantageously used in making blends of gasoline with various other materials, for example propyl amine, methyl ethyl ketone, and in general organic compounds which are mutually soluble in gasoline and pine oil. It will be understood that pine oil may be used alone as a blending component for gasoline but its principal advantage is as a mutual solvent for gasoline and some other material which is to be added to it.

Where I have referred to pine oil I mean in particular a material which is generally known in commerce under that name, or as pine needle oil or fir oil, a bright yellow, volatile, thin liquid containing as chief constituents pinene, sylvestrene, limonene, and bornyl acetate, such as is obtained by distillation of the leaves, or other parts, of various conifers. Pine oil of this class usually has a specific gravity of about 1393-905, and boiling point of 150-l85 C. The invention is not limited, however, to any particular kind of pine oil but includes them in general, as well as any constituent of pine oil which has the essential blending action of pine oil itself. In the appended claims, the term pine oil includes such constituents.

There may be added to the blends herein described one or more of any desired additional substances such as, for example, aromatic compounds of the type of benzol, metallo-organic anti-knock agents such as lead tetraethyl and the like, gum inhibitors such as alpha naphthol, cresol, etc., thickeners such as cobalt naphthenate, polymerized isobutylene and the like.

I do not claim herein the addition of gum fluxing oils to gasoline generally, as this forms the subject matter of a copending application Serial No. 658,153 filed February 23, 1933 by Reginald G. Sloan and Jones I. Wasson.

Various modifications may be made within the scope of the appended claims, in which it is my intention to claim all novelty in the invention as broadly as the prior art permits.

I claim:

1. A motor fuel comprising, as its major constituent, a gasoline containing gum-forming constituents, and containing a sufilcient amount of an alcohol to improve the knock rating of the gasoline, a sufiicient amount of pine oil to hold the alcohol in solution in said gasoline, and from 0.2 to 2.0 parts by volume of the blend of a material normally existing in the liquid phase at both the minimum and maximum temperatures of those parts of a motor on which gum tends to deposit during operation thereof, having a low vapor pressure at the maximum temperature of said parts and having an ability to soften, loosen, dislodge and/or prevent deposition of hard carbonaceous gummydeposits on the Walls, valves, rings and other interior parts of an internal combustion engine comparable to that possessed by a naphthenic type oil having a kauri butanol number higher than 15, a viscosity at 100 F. between 75 and 400 seconds Saybolt, an A. P. I. gravity number between 18 and 28 and a viscosity index less than 30.

2. A motor fuel comprising as its major constituent, a gasoline containing gum-forming constituents, and containing a sufiicient amount of an alcohol to improve the knock rating of the gasoline, a sufficient amount of pine oil to hold the alcohol in solution in the gasoline, and from 0.2 to 2.0 parts by volume of the blend of a naphthenic type lubricating oil having a. kauri butanol number higher than 15, a viscosity at 100 F. between 75 and 400 seconds Saybolt, an A. P. I. gravity number between 18 and 28, and a viscosity index less than 30.

FRANK A. HOWARD. 

